Surface covering materials, especially covering materials used in flooring, should have aesthetic appeal in addition to meeting several functional requirements. In order to meet the often antagonistic functional requirements, surface covering materials are often layered composite structures wherein each layer provides for one or more of the desired functional properties. For example, the top layers of the surface covering provide stain and wear resistance but must also provide for visually appealing patterns or designs. The top layers may include a top, transparent or translucent, wear layer that imparts wear resistance to the surface covering and an underlying decorative layer containing an aesthetically pleasing design or texture. Intermediate layers of the surface covering, not directly visible, may include a high compliance layer providing for a “cushioning” effect but may also be used to provide for embossed relief designs for the surface covering. The bottom layers of the surface covering may be used to incorporate dimensional stability, tear resistance, and strength to the surface covering material.
It is known that the incorporation of small particles into the decorative layer of a surface covering enhances the aesthetic appeal of the surface covering. For example, U.S. Pat. No. 5,627,231 ('231) filed Aug. 11, 1994 and herein incorporated by reference in its entirety, disclosed the incorporation of methacrylate particles into a PVC wear layer. The '231 patent also disclosed the swelling of the methacrylate particles caused by absorption of plasticizer into the particles during the gellation of the PVC wear layer. Although the '231 patent describes the swelling of the methacrylate particles as “substantial”the competition between the methacrylate and PVC particles for the plasticizer limited the swelling of the methacrylate particles. In addition, swelling of the methacrylate particles reduced the amount of swelling of the PVC particles, thereby affecting the thickness of the wear layer. Furthermore, the swelled methacrylate particles became sticky and soft and compromised the top coat. The resulting top coat exhibited poor wear characteristics and was more susceptible to dirt pick-up.
Therefore, there still remains a need to provide a coating composition having a surface texture with improved aesthetic and abrasion resistant properties and to provide a method for manufacturing such coatings.